<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:myObj="urn:myObj">

	<xsl:template match="data">
		<circles>
			<xsl:for-each select="circle">
				<circle>
					<xsl:copy-of select="node()"/>
					<circumference>
						<xsl:value-of select="myObj:Circumference(radius)"/>
					</circumference>
				</circle>
			</xsl:for-each>
		</circles>
	</xsl:template>
</xsl:stylesheet>
